Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net loss	$ (60,089)	$ (290,478)	$ (139,213)	$ (363,443)
Other comprehensive (loss) income, net of tax:
Change in unrealized gains related to marketable securities	(249)	18	23	741
Reclassification adjustments for realization of gain on sale of marketable securities included in net loss	(6)	(322)	(6)	(322)
Foreign currency translation adjustments	(69)	0	(98)	0
Total other comprehensive (loss) income	(324)	(304)	(81)	419
Comprehensive loss	$ (60,413)	$ (290,782)	$ (139,294)	$ (363,024)